Authors: Jonathan Kleinman*, University of Alabama, Justin Hart, University of Alabama
Topics: Biogeography, Environmental Science, Natural Resources
Keywords: wind; salvage; compound disturbance; longleaf pine; floristic composition
Session Type: Paper
Start / End Time: 10:00 AM / 11:40 AM
Room: Zulu, Sheraton, 8th Floor
Presentation File: No File Uploaded
Increasing anthropogenic pressures and climate change may expose forests to more frequent and severe disturbances. High-severity disturbances in quick succession (i.e. compound disturbances) may initiate novel forest successional and developmental patterns. This study documents the singular and synergistic effects of an April 2011 EF3 tornado and subsequent salvage harvesting operation over the background disturbance of prescribed fire in longleaf pine woodlands of the Alabama Fall Line Hills. Physical and floristic data were collected May–June 2016 and 2017 in areas undisturbed, wind-disturbed, and compound-disturbed (wind-disturbed and salvage-harvested). Multivariate analyses revealed distinct floristic differences across disturbance categories. Biophysical drivers most correlated with differences in floristic assemblages included coarse woody debris volume, sapling density, canopy cover, and basal area. Overall, 192 plant taxa were documented. Wind-disturbed plots had the greatest plant richness (160 taxa) and diversity, and contained indicator species with unique habitat requirements. Indicator species of compound-disturbed plots were mostly generalists with broad habitat requirements. Reduced plant richness (126 taxa) and diversity on compound-disturbed plots was attributed to salvage harvest-mediated reductions in habitat heterogeneity and resource availability. Leaving patches unharvested within salvaged stands may support greater stand-scale plant diversity, and serve as a compromise between ecological and economic objectives. Interestingly, regeneration of longleaf pine, the most desirable species in the system, increased with collective disturbance severity. Nonetheless, small-statured longleaf pines were markedly outnumbered by other woody plants, indicating that these woodlands may need competition reduction measures beyond prescribed fire for recovery toward longleaf pine dominance.